This invention relates to processing of transmitted electronic information and more specifically to real-time compressed video data techniques.
Numerous applications exist today requiring large amounts of digitized video data to be transmitted for reception and interpretation at a remote location. Many of these applications, such as remote controlled vehicles, video teleconferencing, guidance control systems, surveillance systems or other video sensing applications, require real-time or near real-time processing of transmitted information. In order to satisfy throughput requirements of the transmitted information, data compression techniques provide for approximating certain transmitted data based upon selection criteria sometimes tailored to specific applications. These compression techniques tend to sacrifice a certain amount of preciseness for lower data rate or computational simplicity.
In any given data transmission an instantaneous representation or "snapshot" of the information to be transmitted is captured and processed in a manner consistent with the intended receiver technology. These individual snapshot representations are routinely updated, processed and transmitted to provide a reasonable approximation of the actual scene to the displayed image.
In video transmissions the snapshot is represented by an individual frame which is comprised of strategically ordered picture elements (pixels). The frames are transmitted at a specific rate, such as 30 frames per second, thereby providing the updated status of the processed information. The individual video frame is typically composed of a uniform number of picture elements such as 245,760 pixels for a 512.times.480 array.
Since individual pixels consist of several bits of binary information representing a defined color or shade, it is possible and well known to process the pixels in defined p.times.p data blocks. Depending upon the timing and resolution requirements, a variety of techniques may be employed to perform data compression within any given frame. While such data compression is useful, most current video data transmission systems provide more information (frames) than can be economically received and processed in real-time in terms of hardware for a required data bandwidth for data. Current solutions mainly focus upon data compression using high cost, high resolution approaches.
Current fielded video compressors adjust compression thresholds by determining after-the-fact how much compressed data was produced for a given threshold setting and using the fullness or emptyness of a first-in-first-out memory to either increase or decrease the threshold setting. This methodology of threshold "guessing" used in the prior art is eliminated by the teachings of this application.
There exists a need for improved economical compression techniques that minimize guessing, high cost and latency deficiencies.